Typewriting machine



June 11, 1940. 4 w, HELMQND 2,204,249

TYPEWRI'IING MACHINE Filed May 14, 1957 2 Sheets-Sheet 1 wwwwaw g 72 Y 47 a r B ii omm INVENTOR.

June 11, 1940. HELMOND 2,204,249

TYPEWRITI NG MACHINE Filed llay l4, 1937 2 Sheets-Sheet 2 Patented June '11, 1940 UNITED STATES TYPEW RITIN G MACHINE William F. Helmond. West Hartford, Conn, assignor to Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware Application May 14, 1937, Serial No. 142,528

2 Claims.

This invention relates to the muting of vibration in the type-bars of typewriters.

Vibration of the type-bar impedes its passage into the type-bar center guide, causes the type face to make an indistinct impression on the work-sheet, reduces the number of legible carbon copies, and increases the noise of typing and the Work necessary for the operation of the typebar.

It is an object of this invention to reduce or eliminate the Vibrations of the type-bar and increase the legibili'ty of the work-sheet, increase the number of legible carbon copies, minimize or eliminate the noise and decrease the energy expended by the typist.

One form of this invention is a type-bar made in longitudinal halves, of the same material and thickness, as each part may be half of the thickness of a standard type-bar. The halves are to 1 be spot-welded together at one or more scattered points approximately along the longitudinal axis. The halves of the type-bar, being of the same thickness and material, will have the same sonorousness. When spot-welded together, so that the adjacent inner surfaces of the halves may be in contact, the vibrations of the typebar will be reduced or eliminated. Each half may have a rounded longitudinal strengthening rib. When both halves have the ribs, they may curve outwardly from the contacting surfaces, or the ribs may be so constructed that one rib will be of a size tofit or nest in the rib of the other half. The two halves may have a hole cut in that portion of the type-bar which is in the segment. This hole is to be of such size and so placed that it will aid in muting the vibrations of the type-bar without impairing its strength.

Another form ofthis invention is a type-bar, having a shortened, centrally positioned, vibration-muting metal strip, spot-welded, in one or more places, along one of its side surfaces. The metal strip may be shaped or bent so that when, at or near its end, it is spot-welded to the typebar there will be uniform pressure between the contacting surfaces.

Another form of this invention is a type-bar having a slot cut in that portion farthest from the type-head. The slot is so located that the strength of the type-bar will not be impaired, and will form a portion or projection that will dampen the vibrations of the type-bar.

There is also shown a type-bar having a vibration-reducing, round hole located in the hub portion of the type-bar. The hole is of such a size and location, that it will not impair the strength of the type-bar, but will remove that portion which usually has convex surfaces, or humps, which have been unavoidable when grinding the type-bar by hand. Hence there is secured an accurate fit of the type-bar in the slot of "the segment.

A disk of a slightly smaller diameter, and from two to four thousandths less in thickness than the type-bar, may be inserted in the hole and held there by the enlarged, lower, portion of the segment. This vibration-dampening disk is rotatable both around its own axis and also around the fulcrum of the type-bar. The inertia generated by swinging the type-bar will cause the disk to rotate on its own axis and it will carry and throw oil into the guide-slot, in the segment, in which the type-bar fits and a protective lubricating and vibration-dampening film of oil will be maintained on the contacting surfaces of disk, type-bar and segment.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure l is a side elevation of a typewriter showing the platen, segment and a center action.

Figure 2 is a side elevation of a type-bar made in two pieces.

. Figure 3 is a section of Figure 2, taken along the approximate longitudinal line of weld points.

Figure 4 is a section of Figure 2 on the line 4-4.

Figure 5 is the same as Figure 4 except the ribs are nested.

Figure 6 is a side elevation of a type-bar, segment, and platen.

Figure '7 is an elevation of the same action shown in Figure 6. The type is near the point of contact with the work-sheet.

Figure 8 shows the type-bar of Figure 6 in printing position.

Figure 9 is a partial section along a plane at right angles to plane of Figure 6.

Figure 10 is a section along the line Ill-I0 of Figure 6.

Figure 11 is an elevation of a type-bar having a metal strip spot-welded to it.

,Figure 12 is an exploded plan view of Figure 11.

Figure 13 is a plan view of Figure 11.

Figure 14 is a section along the line l4|4 of Figure 11.

In Figure 1, the key-lever 20 of a type-action in an Underwood typewriter has been depressed, though usually held in a normal inoperative position by the spring 22, by pressure on the keybutton 2!. The key-lever 20, which is pivoted on the rod 23, carries a headed pin 24, engaging a slot 25 cut in an arm 26 of the bell-crank 2l, pivoted on the rod 28. The upper end of the arm 29 of bell-crank 21, has a hole 30 in which is fastened one end of the wire 3|. The other end of the wire 3| engages a hole. located in thetype-bar 32, pivoted on the rod 33 mounted in the segment 34. Type-bar 32 has the typeing the projecting portion 43 of the type-bar 32..

The universal bar 44 is held against a curved portion 45 of the type-bar 32 by the spring 46.

The lower portion of the segment 34 has slots 41 into which a part 48' of the type-bar'32 fits. Having a slot 50 cut in thesegment-engaging portion 48 of type-bar 32, in sucha'manne'r as to leave a projection 5|, reduces the vibration of type-bar 32.

Figures 2-34 show a type-bar 32 constructed of halves. 53 and 54. Halves 53 and 54 are spotwelded together at one or more loci 55. Loci 55 are located approximately along the axis of the type-bar 32, leaving the edges of 53 and 54 free.

The halves 53 and Y54 may be of the same thickness and material and may be half thethickness.

of a standard type-bar. Therefore each half 53 and 54 has the same sonorousness and. when spot-welded together along an axial linethey will. One or both halves 53 and 54 may have ribs 56 and 51 for additional.

mute any vibrations.

strength of the type-bar 32, and if both halves 53 and 54 haveribs 56 and 51 they may be constructed to curve away from each other, as shown in Figure 4, or they may be constructed to nest as shown in Figure '5. Halves 53 and 54 may have a hole 58, located near the pivot rod 33 and cut so as not to impair the strength .of the type-bar 32, but will aid in muting the vibrations of type-bar 32. Thetype bar 32, made of halves 53 and 54, pivots on the rod 33 mounted in segment 34, and has the hole 4| for wire 3|, and is located and operated as shown in Figure 1.

--.In Figures 6-9 inclusive, the segment 34 has an enlarged slotted portion 59, which has the slots 41, into which the type-bars 32 fit. The type-bar 32, shown in these figures, has a hole 60, near the pivot rod 33 for. muting thevibration. In hole 66 there may be inserted a disk 6| slightly smaller in diameter than hole 66, and from two to four thousandths thinner than typebar 32. Disk 6| is held in position by the slotted enlarged portion 53 of segment 34. Oil may be placed in the segment slots 41 and will, from the force of gravity, form a drop 62 at the bottom of disk 6|, as shown. in Figure 6. .When type-barthe drop of oil 62 into the upper portion ofv slot 41, from where it distributes itself over sides of slots 41, the disk SI. and type-bar 32. This film of oil acts as lubricant and to mute the vibra-i tions of the type-bar- 32. Disk 6| is an aid for muting vibration of type-bar 32. g l In Figure 10, is shown how the hole 66 removes the portion 65 of type bar 32 which has curved faces dueto grinding by hand. The removal of this portion 65 gives a more accurate fit in slots 41 and reduces friction, thereby aiding in muting the type-bar 32. I

,,In Figure 11, the type-bar 32 is pivoted on rod 3,3'insegment 34 similar to Figure 1. This typebar; 32.has a shorter metalstrip 64 spot-welded.

in one or more loci 55, along one side. The metal strip 64 may have a part of one end 66 straight or parallel with the type-bar 32, and the rest of the metal strip i64 curvedtoward the plane of type-bar'32, as shown in Figure 12: When welded together as in Figure 13, the metal strip 64 will contact the type-bar 32 with uniform pressure throughout its length. The metal strip 64 mutes the vibrations of type-bar 32. Type-bar 32 may have ast'rengthening rib 51 which curves away from the, side where the metal strip 64 is, as shown in'Figure 14;

The type-bar 32 may vibrate from one or all of the following causes: impact on the keybutton 2|, friction of the type-bar 32 in segment slot 47, impact. of type-bar 32 against stop-ring 46, impact and friction of the type-bar-guiding projection 43, and type-bar guide 42, impact of type-faces 36 on work-sheet 31, inertia of the type-action, and imperfect alignment of the type-bar 32, or any of the parts of the type: action- Thisvibration impedes the progress of projection 43 in type-guide 42, causes imperfect contact between type 36 and work-sheet 31 which gives a blurred indistinct typed letter, causes the force of impact of type 36 to be reduced, thereby reducing the number of legible carbon copies, causes an increase in the noise of operation of a typewriter, and causes an increase in work necessary for operating the type-action.

The vibration of type-bar 32 may be muted by constructing the type-bar as shown in Figure l, as shown in Figure 2,.as shown in Figure 6, with or without the disk 6|, or as shown in Figure 11.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be, used without others.

Having thus described my invention, I claim: 1. In a typewriter, an elongate type-carrying bar integral in its extent from end to end, a1

type head being secured to one end of said bar, saidbar having a type-guide-entering neckportion immediately below said type head, and a snubber strip attached to said bar solely for the purpose of muting its vibrations, said strip being materially shorter, than said bar and placed thereon, between the neck-portion and the opposite end portion of said bar, so that the ends of said strip do not overlap either of said portions and hence do clear said portions, said opposite end portion of the bar being disposablein a typebar-i'ulcruming segment.

2. In a typewriter, an elongate type-carrying bar integral in its extent from end to end, a type head being secured to one end of said bar, said bar. having a type-guide-entering neck-portion immediately below said type head, and a snubber strip attached to said bar solely for the purpose of mutingits vibrations, said strip being materially shorter than said bar and placed thereon, between the neck-portion and the opposite end portion of said bar, so that the ends of said strip do not overlap either of said portions and hence do clear said portions, said opposite end portion of the bar being disposable in a type-bar-fulcruming segment, said strip being of resilient material and being attached at only one of its ends to said bar, the remainder of the strip being unattached and resiliently sprung against the side of the type-carrying bar substantially as set forth.

WILLIAM F. HELMOND. 

